1. Field of the Invention
The present invention relates to a light guide plate, and a surface light source device and a transmissive display apparatus that are provided with the light guide plate.
2. Related Art
A transmissive display apparatus has been known that displays an image by illuminating a transmissive display unit such as a Liquid Crystal Display (LCD) panel from a backside thereof by a surface light source device (back light). Surface light source devices can be roughly classified into a direct lighting type in which a light source is disposed directly below an optical member and an edge lighting type in which a light source is disposed on a side of an optical member. A surface light source device of the edge lighting type has been widely used recently, which can reduce thickness thereof compared to the direct lighting type through disposing the light source on a side of the optical member.
In the surface light source device of the edge lighting type, a light source is disposed at a position facing a side face (a light incident surface) of a light guide plate. Light emitted by the light source is incident upon the light guide plate from the light incident surface and travels in a direction (light guiding direction) substantially orthogonal to the light incident surface while being repeatedly reflected by the light guide plate and a reflective surface facing the light guide plate. By changing a traveling direction of the light by means of diffusion patterns and the like provided on the reflective surface of the light guide plate, the light gradually exits toward an LCD panel from the light exit surface, positions along the light guiding direction (for example, see Cited Publications 1 and 2).
Patent Document 1: Japanese Unexamined Patent Application Publication No. H9-43433
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2007-227405